Re: Help with slow model translation

On 2/21/20 5:46 PM, Greg Gruber wrote:
> Hello,
>
> I have a model that I have developed using MathProg, that I am using
> regularly. Some problem datasets result in very large models. The
> problem itself is solving very quickly, but I am finding the model
> translation (reading the .mod file, data files, and setting up the
> problem) to be very slow.
>
> I came across this on the wikipedia entry: " The take-home message is
> that nested set iterations should be avoided where possible, as these
> greatly expand the dimensionality and size of the model space to be
> processed.", and it discusses a case on the OSeMOSYS energy model where
> the execution time was reduced from 15 hours to 9 minutes by a
> reformulation.
>
> Unfortunately, I'm not sure what they mean here, and I am looking for an
> example. I have tried searching the OSeMOSYS site for more information,
> as well as searching for publications by Jonas Horsch, who did the
> reformulation, but have had no luck yet.
>
> Does anybody have examples illustrating how to avoid nested-set
> iterations in MathProg?
>
> Thanks in advance,
> Greg
>
Hello Greg,

please, provide an example model which shall be simplified.

Best regards

Heinrich
>